The present invention relates to an art to properly control lighting from a vehicle headlamp while taking into consideration traveling road and environmental conditions.
The Intelligent Transport System (ITS) calls for solving technical problems about warning vehicle drivers of dangers, making them evade dangers, automated driving and so forth; for example, it is regarded as being important to establish the art of recognizing environments around vehicles such as obstacles on roads and recognizing traveling roads, and enhancing its reliability.
There is a known apparatus for controlling light distribution by varying the direction of emission of light from a lighting device and an irradiation range in response to variations in the travel condition of a vehicle and the traveling road. However, it is still preferred to control light distribution on precisely securing information concerning traveling roads and the ambient environment with the sufficient intensity of illumination in the forward field of vision and reducing the influence of dazzling light on oncoming vehicles, road users and so forth as much as possible.
In order to acquire data on the configuration of a road on which one""s own vehicle is driven, the following apparatus can be referred to.
An image processing system for extracting lane marks and the like on the basis of image information from an on-vehicle camera in order to recognize an intersection, a specific position on the road surface, the curvature radius of the linear form of a road and so forth.
A system for acquiring the present position of one""s own vehicle and the environmental information based on map information from a navigation apparatus for use in guiding a route and the like.
However, the conventional apparatus still develop problems in the following respects.
In the first method using the on-vehicle camera, though recognizing capability can satisfactorily be demonstrated and though distance measurement precision is relatively high in case where a good visual field is assured in the daytime, the luminance of a lane mark as an object to be detected tends to become lowered as the distance from the vehicle increases, for example, in case where a sufficient quantity of lighting is unavailable during night traveling and the problem is that the lane detection capability is lowered. Moreover, inconvenience is caused by the fact that there recognition performance is affected by the weather condition. For example, there are problems arising from a decrease in luminance contrast that is caused by scattering originating from an optical screen phenomenon due to rainy weather and fog, a decrease in lane recognition performance originating from a surface reflection phenomenon due to a water on the road, infeasibility of lane mark detection on the snow and so forth.
In the second method using the navigation apparatus, as map matching precision regarding the present position of one""s own vehicle lowers in case where the vehicle is driven on a road having few changes of direction for hours or where the vehicle is driven in a road between tall buildings in the urban area, in the mountainous area or the like, it becomes hardly possible to accurately make a decision on a curved road and the position of an intersection that are necessary for controlling lighting. Moreover, there is the fear of making lighting control entirely improper to the condition of the road on which the vehicle is being driven in case where a wrong route is taken.
In a road map schematically shown in FIG. 16, for example, a thick line shows a national highway a, and a road b running in substantially parallel thereto shows a prefectural highway. Further, a route R shown by a broken line therein shows an actually selected route and a route Rxe2x80x2 shown by a chain double-dashed line shows a route predicted by the navigation apparatus.
In case where there exists a road (the national highway) extending in parallel and close to a road (the prefectural highway) on which the vehicle is being driven, the probability for mistaking the national highway as a high-grade road for the route is high, which may result in making lighting control improper to the actual state of a road to be taken.
An object of the present invention is to exert proper, highly reliable lighting control in harmony with travel environment in which a vehicle is driven.
In order to solve the foregoing problems, a vehicle headlamp apparatus according to the invention comprises: map information acquiring means for acquiring positional information on one""s own vehicle on a map and the environmental information, environmental condition detection means for detecting an environmental condition relating to a traveling road on which one""s own vehicle is driven according image information or the information acquired from a radar, and light distribution control means for varying the light distribution of a headlamp attached to a vehicle in accordance with variation with the travel condition of one""s own vehicle and the environmental condition, wherein the light distribution control means performs light distribution control over the headlamp according to one of both kinds of information adopted with the priority given thereto out of the information derived from the map information acquiring means and the information detected by the environmental condition detection means or according to the information complemented with both kinds of information above.
Therefore, according to the invention, the priority is given to more reliable information out of the information derived from the map information acquiring means and the information detected by the environmental condition detection means so as to perform light distribution control over a lighting device or to perform light distribution control over the lighting device according to the modified information complemented with the difference between both kinds of information, so that forward irradiation light on the traveling road of the vehicle is satisfactorily secured by using highly reliable detected information and that travel safety is enhanced.